Re: One pound of Plutonium -Reply

[ABELQUIE@ORAU.GOV]

Dear Otto and all:

I have been keeping abreast of the LN-T argument for many months on
Radsafe.  I  have no direct experience to base my opinion for or against
the LN-T hypothesis.  I rely on the merits (based on my perception)  of
each side of this argument.  It appears to me that it is likely that a
threshold exists.  So, for sake of argument, let's say that a threshold
does exist---How do the regulators apply it?  I posed this same question
to Keith Dinger last week and his quick reply was "set limit at 10% of
threshold".  I'd appreciate other  thoughts on this.

In your example below, the threshold is 1 Gy lifetime dose for Pu.  Let's
assume that a threshold for penetrating radiation is shown to exist at 25
rem - the problem is, how do the regulators implement this "scientific
fact" (existence of a threshold)?   Do we ever expect to know what the
probability of fatal cancers are once the threshold is exceeded?  Do we
consider the 300 or so mrem/y from background as contributing to the
lifetime dose?  I think that once a threshold is proven to exist, people will
want to spend sufficient resources to be assured that they will have a
very small chance of exceeding the threshold.  Thus, I believe that even
if LN-T soon goes away, we will still have ALARA - but I believe a much
more reasonable form of ALARA (i.e not having to spend $$millions to
reduce mrem).   It would be nice to hear some discussion from the
Radsafe community on this.      


>>> D1.OUT."ograabe@ucdavis.edu" 03/23/98 11:17am >>>

March 23, 1998
Davis, CA

Dear Jesse and all:

There is no truth to ANY risk factor in FGR 13. Your use of FGR 13 in
your
calculation makes totally invalid the result that you got. I have
previously estimated that there is an effective threshold for
radiation-induced lung cancer from plutonium at about 1 Gy lifetime dose
(HPJ 57, Suppl 1, 419-432, 1989). The Russians found that no one with
lifetime lung doses below 0.8 Gy developed radiation-induced lung
cancer
(HPJ, Dec. 1997). FGR 13 will never give you a correct answer since the
whole document is based on an imaginary linear risk relationships that
have
no basis in reality.

Otto
                *****************************************************
                Prof. Otto G. Raabe, Ph.D., CHP
                [President, Health Physics Society, 1997-1998]
                Institute of Toxicology & Environmental Health (ITEH)
                     (Street address: Old Davis Road)
                University of California, Davis, CA 95616
                Phone: 530-752-7754  FAX: 530-758-6140 [NEW AREA CODE]
                E-mail ograabe@ucdavis.edu